Knife sharpener



July 16, 1946. J BARNES 2,404,025.

KNIFE SHARPENER Filed 061;. 6, 1944- A llilll l HM INVENTOR. Jase v71 L.Barnes Patented July 16, 1946 UNITED STAT ES PATENT OFFICE KNIFESHARPENER Joseph L. Barnes, Indianapolis, Ind.

Application October 6, 1944, Serial No. 557,427

Claims.

My present invention relates to a knife sharpener of the kind having apair of rotary files between which the knife blade may be drawn forsharpening it.

One object of the invention is to provide a knife sharpener of simple,durable and inexpensive construction comprising a base and a pair ofrotary files or other suitable abrasives, mounted thereon.

Another object is to provide a means to permit rotation of the files inone direction and prevent their rotation in the other direction as aknife blade is reciprocated between them.

Still another object is to provide a knife sharpener which can be easilyused by any unskilled person and operated merely by a reciprocatingmotion of the knife blade while held between a pair of rotary files.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of mydevice whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in my claims and illustrated in theaccompanying drawing, wherein:

Figure 1 is a plan view of a knife sharpener embodying my invention andshowing in dotted lines the relation of a knife thereto while beingsharpened.

Figure 2 is a front elevation of the knife sharpener showing a knifeblade in section, and

Figure 3 is an enlarged sectional view on the line 33 of Figure 2.

On the accompanying drawing I have used the reference numeral ill toindicate a base which is preferably rigidly mounted on a table orcabinet top as by countersunk screws I2.

Thebase it has a pair of shoulder rivets l4 extending upwardly therefromwhich are peened as at [B to retain them in position. On each rivet arotary file I6 is journalled. The shouldered character of the rivetsprevents any binding of the files and permits them to rotate freely.

The files I6 are provided with teeth It as illustrated in Figure 3 andthe teeth of one file point clockwise while those on the other pointcounterclockwise. The files l6 are in the shape of cone frustums tobevel the sides of a knife blade as indicated at t8, the blade itselfbeing designated 20. The teeth i8 as will be noted in Figure 3 mesh witheach other so that there is an overlapping of the peripheries of thefiles at their lower ends as shown in Figure 2, thus presenting filefaces entirely down to the lower sharp edge of the knife blade. Thiseliminates the wire edge caused by ball types of sharpeners wherein theballs contact each other. With respect to those types of sharpenershaving rotary files provided with three files instead of two, myarrangement eliminates the necessity of the third file.

The teeth I8 may be considered as cutting in one direction, that is whenthe knife is drawn downwardly in Figure 3. I provide a wedge-like stopor holding pawl 24 coacting with the files which is spring-presseddownwardly in Figure 3 by a spring 26. The stop 24 floats on a pin 28extending upwardly from the base l0 and, accordingly, as the knife isdrawn toward the user, the stop wedges in between the rotary files andthey are held so that their cutting teeth l8 act upon the knife tosharpen it. When the knife is pushed away from the user, the frictionbetween the knife and the files will rotate the files (clockwise for theright hand one and counter-clockwise for the left hand one), this beingpermitted by the holding pawl 24 backing up due to such rotation. Thusthe teeth 13 act only when the direction of travel of the knife bladerelative to them is such that they can cut metal therefrom, and thedevice is automatically operable with only the requirement that theknife blade 22 be held down between the files and reciprocated.

Abrasives other than files such as carborundum or the like may beemployed and other changes may be made in the construction andarrangement of the parts of my device without departing from the realspirit and purpose of my invention, and it is my intention to cover bymy claims any modified forms of structure or use of mechanicalequivalents which may be reasonably included within their scope withoutsacrificing any of the advantages thereof,

I claim as my invention:

1. In a knife sharpener of the character disclosed, a base, a pair ofrotary abrasive elements thereon, said abrasive elements being shaped asfrustums of cones and having intermeshing teeth at their lower edges,and wedge means for permitting rotation of said abrasive elements in onedirection and preventing their rotation in the opposite direction, saidwedge means being constrained to wedging position between said abrasiveelements.

2. A knife sharpener comprising a base, a pair of frustum shaped rotaryabrasive elements thereon. having teeth meshing with each other at thebases of the frustums, and a holding pawl spring urged to wedgebetweensaid elements and stop their rotation as a knife blade is drawn betweenthem and to release and permit their rotation as the knife blade ispushed in the opposite direction.

3. A knife sharpener comprising a pair of frustum shaped rotary abrasiveelements having teeth meshing with each other at the bases of thefrustums, and a. holding pawl to wedge between said elements and stoptheir rotation as a knife blade is drawn between them.

4. In a knife sharpener of the character disclosed, a pair of rotaryabrasive elements, said elements being frustum cone shaped, and a wedgebiased to frictionally engage between said elements for permitting oftheir rotation in one direction and preventing their rotation in theopposite direction.

5. A knife sharpener comprising a base, a pair of frustum cone shapedrotary abrasive elements thereon, and a holding pawl spring urged towedge between said elements and stop their rotation as a knife blade isreciprocated between them in one direction and to release and permittheir rotation as the knife blade is reciprocated between them in theopposite direction.

JOSEPH L. BARNES.

